Geographic information systems provide for the archiving, retrieving, and manipulating of data that has been stored and indexed according to geographic coordinates of its elements. A geographic information system can be used for storing, manipulating, and displaying a three-dimensional model of a geographic area. An interactive geographic information system can present a graphical representation of the three-dimensional model to a user in a suitable user interface, such as a browser. A user can navigate the three-dimensional model by controlling a virtual camera that specifies what portion of the three-dimensional model is rendered and presented to a user.
The three-dimensional model can include a polygon mesh, such as a triangle mesh, used to model the geometry (e.g. terrain, buildings, and other objects) of the geographic area. Geographic imagery, such as aerial or satellite imagery, can be texture mapped to the three-dimensional model so that the three-dimensional model provides a more accurate and realistic representation of the scene. Typically, a single base texture is texture mapped to the polygon mesh regardless of the viewpoint of three-dimensional model. The single base texture can be optimized based on viewing the three-dimensional model from a plurality of differing viewpoints for the scene. For instance, the geographic imagery mapped to each polygon face (e.g. triangle face) in the polygon mesh can be selected according to a selection mechanism or algorithm that favors geographic imagery with a direct or near direct view of the polygon face.
In certain circumstances, a view-dependent texture can be rendered in conjunction with the three-dimensional model when the virtual camera views the three-dimensional model from a perspective associated with a reference viewpoint, such as a canonical viewpoint (e.g. a top-down or nadir perspective, a north perspective, a south perspective, an east perspective, and a west perspective). The view-dependent texture can be optimized for viewing the three-dimensional model from a single view direction associated with the reference viewpoint.
In cases where the virtual camera is not orthographic, objects rendered near the edges of the field of view defined by the virtual camera can be viewed from a direction that is different from the reference direction associated with the view-dependent texture. This can cause visual artifacts in the representation of the three-dimensional model. For instance, taller buildings rendered near the edge of the field of view can have a streaky appearance along the face of the building.